MapDiffsExtension<K, V> extension Null safety



recast<KK, VV>(MapDiffArguments<KK, VV> args) MapDiffs<KK, VV>
undelegate<K, E>(MapDiffArguments<K, E> args) MapDiffs<K, E>
This occurs when the diff was delegated - which means that instead of passing the real instance to the isolate, we passed a safe delegate. When the method returns, we need to rehydrate the results by looking the delegates up in a map.